Powers and abilities:
Superhuman Physical Characteristics, Magic, Reality Warping, Non-Existent Physiology (Sensories bodies are made of "complete nothingness", making most if not all conventional attacks just pass through him), Enhanced Senses, Extrasensory Perception, Soul Manipulation and Immunity to it (Mercurius’ sensories lack souls), Immortality (Types 1, 5 and 9. Relies on his true body which exists outside of Reality and cannot be killed) , Telepathy, Mind Manipulation (Able to instill anxiety with his mere presence and bloodcurdling rage with his words, can also emit an immense pressure that is "heavy enough to stick and burden the very soul" and causes those around him to forget how to breathe and think when he reveals his "true self"), Dimensional BFR, Can travel to other dimensions (Including Marie's world, the Twilight Beach, which exists outside of even the Throne itself), Can make attacks "vanish" from existence, Transmutation (Transmuted parts of Reinhard's castle/Briah to create a sword and fight Ren with), Possesses incredible willpower, Durability Negation, Immunity to natural poisons and diseases, Resistance to Magic, Mental, Spatial, Temporal and Conceptual attacks.
Attack Potency: At least Universal (stated to have the firepower necessary to overcome the Divine Vessel's durability), can ignore durability by attacking his opponent's soul.)
Speed: Speed: At least FTL, likely FTL+ (Easily kept up with Ren in their small fight, should be comparable to Reinhard)
Durability: Universe level
True Form/Hadou God:
Power Summary: Some of the previous abilities in addition to Immortality (Types 3, and 10. Transcends the concept and dimensional idea of Death and is unkillable by anyone less than his Level of existence), Law Manipulation, Conceptual Manipulation (Type 1, Full control of total concepts and ideas including the existence of an individual or even abstracts), Causality Manipulation, Space-Time Manipulation, Probability Manipulation, Nonexistence Manipulation, Regeneration (High-Godly; can regenerate from conceptual destruction), Acausality (Type 5. Exists outside of Reality and dimensional space, making himself separate from all Space-Time affecting abilities and immune to Time-related paradoxes), Information Manipulation, Telekinesis, Teleportation, Gravity Manipulation, Abstract Existence , Non-Corporeal, Cosmic Awareness, Nigh-Omniscience, Nigh-Omnipresence (Full Omnipresence in his own territory), Beyond-Dimensional Existence ), Large Size (Type 11, the size to his power is unreachable even by stacking infinities upon infinities), Summoning (Can summon the Physical Manifestation of his Law), and able to manifest avatars in order to interact outside the Throne.
Attack Potency: High Outerverse level (As a Hadou God, Mercurius exists completely above and external to all expansions of the Singularity - of which size corresponds to the inner depth of the Throne God, reaching up to infinite levels each transcending the last - which in turn utterly transcends the Multiverse, no matter the qualitative dimensions/layers it may have. To even the weakest God with 1 Taikyoku, an object that governs All Of Creation such as the Throne is nothing more than a tool. Destroyed said throne in the battle between Reinhard and Mercurius. Effortlessly killed Nerose Satanel when he came to being in the latter God's world. The source of his power, Taikyoku, is responsible for the existence of all reality, including dimensional space itself. Additionally, Mercurius has a Taikyoku value of 90, making him one of the strongest possible Hadou Gods).
Speed: Nigh-Omnipresent normally, Omnipresent in his own territory
Durability: High Outerverse level (Tanked strikes from Reinhard)
Vive Memor Mortis - Acta Est Fabula: (Live Mindful of Death - The Play is Over) The manifestation of Mercurius’ Law, “To experience the unknown, dying in the arms of Marie. Absolutely any other end than that, is unacceptable”. When his Law is activated at the time of his death, Mercurius will reset everything if it does not end how he wants it to end, even in realms where time is nonexistent such as the Throne. While everything is resetting, Mercurius is able to change the next timeline in whatever way he likes (Such as erasing any factors leading to Hajun’s rise after the events of Marie’s route) and this power even allows him to bring back the Throne itself (a place where no form of time exists) after it is destroyed (ex. his fight against Reinhard) and those whose entire existences were wiped out completely with no chance of recovery (as this was able to bring back Ren, Reinhard, and Marie after they died and won fighting against Hajun), albeit the butterfly effect that his changes produce is out of his control. All abilities described below are mere side-effects of his Law.
Sequere Naturam: (You Are to Follow Nature) Mercurius unleashes a Supernovae that consists of thousands upon thousands of stars condensed into a single blast that can atomize Gods from the inside. This move was also powerful enough to have been able to instantly kill Nerose Satanel, a Hadou God equal in power to the likes of Ren and Reinhard during Marie's Route, in one hit.
Dura Lex Sed Lex: (The Law is Harsh But It Is Law) Mercurius creates a Great Attractor which draws everything towards it into a singularity.
Aurea Mediocritas: (The Golden Mean) Mercurius aligns the stars into a Grand Cross, causing an astrological energy surge that can incinerate Atziluth Gods from inside-out.
Omnia Fert Aetas: (Time Robs Us of All) Mercurius makes all of existence into an elementary particle and sends it into the past of the opponent, thus causing a paradox and erasing them from existence.
Disce Libens: (Learn Eagerly) Mercurius condenses all the stars in the multiverse into a black hole that destroys everything. This causes everything in existence to be erased completely, including the Throne itself.
Law of Foreknowledge (Wave of Mercury/Mercurial Curse): Mercurius' Law, the Law of Foreknowledge, has the added effect of "devouring the mind". And Mercurius' Sensory, who embodies this law, is able to "invoke anxiety upon all who laid eyes upon him", and through his "endless babbling" is able to turn that anxiety into irritation, and that irritation into a mindless rage, while simultaneously making those around him feel like it "isn't right" to try and kill him. Mercurius' can also incidentally "reveal his true self" and release a pressure that is "heavy enough to stick and burden the very soul". Even stating that the members of the LDOs' minds and bodies wouldn't be able to take much more of him doing that.
Kamungara: The physical manifestation of a Hadou God's Law, existing as a universe within them. Mercurius' takes the form of a massive Caduceus coiling around all of creation.